Thousands of valuable edition around JavaScript and JSAPI on MDN (See [all his revisions]https://developer.mozilla.org/en-US/dashboards/revisions?user=arai). JSAPI was in a sore state before he started working on it, it isn't any more.

Intense MDN documentation: https://developer.mozilla.org/en-US/dashboards/revisions?user=Noitidart
Expert on js-ctypes and especialy mac os obejctive c, he added the documentation on MDN for it
He even helps extensively with solving other peoples issues: http://www.unmht.org/forum/en/4774.html (this is exmaple of objc jsctypes help)